Secure routing protocol considering load distribution in mobile ad hoc networks

Mobile ad hoc networks (MANETs), where nodes can communicate without an infrastructure, require all nodes to be cooperative enough to transfer packets for other nodes. However, malicious nodes engage in dropping packets improperly. In order to alleviate the influence, secure routing protocols using trust values were proposed. Secure routing protocols discover reliable paths that are comprised of cooperative nodes with high trust values. Here, the trust value indicates the degree of reliance. Though these protocols are effective for reducing the influence by malicious nodes, they causes two problems at the same time. One is a load concentration problem that specific nodes with high trust values are required to transfer numerous packets. The other is an undetected malicious nodes problem. In secure routing protocols, it takes a long time to detect malicious nodes because of the lack of evaluation for the nodes. In this paper, we propose an ad hoc on-demand trusted-path distance vector routing protocol that distributes loads (LD-AOTDV). LD-AOTDV discovers paths that are comprised of the nodes which are not used so much as relay nodes. Thereby, this protocol can distribute loads of relaying packets to the nodes. LD-AOTDV can also detect malicious nodes effectively by evaluating the nodes when they are selected as relay nodes. By detecting malicious nodes quickly, LD-AOTDV can make the network safer. We evaluate the performance of LDAOTDV and compare it with other secure routing protocols. As a result, LD-AOTDV shows better performance than others in terms of load balancing and detection ratio of malicious nodes.